Switch mechanisms



June 16, 1959 E. A. MEOLA 2,891,119

SWITCH MECHANISMS Y Filed Nov. 6, 1957 A a .L N 0 R15 m m an M M V0 NR g 01.4% 2 w. W

2,891 ,119 it Patented June 16, 1959 I SWITCH MECHANISMS Edward A. Meola, West Point Pleasant, NJ, assignor to ItheUnited States of America as represented by the Secretary of the Army .Application'November 6, 1957, Serial No. 694,899

. wwwlC z (Granted under Title 35, U.S.Code (1952), see. 266) A The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon. v

The presentinvention relates to improvements in electric switches. More specifically, the invention relates to push-to-talk switches used in microphones and handsets.

It is an object of this invention to provide an improved push button switch of the above type which is relatively simple in construction and capable of expeditious assembl It is another object of the invention to provide an improved switch of the above type which operates uniformly even though the pressure on the push button varies.

For a more detailed description of the invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawing, wherein:

Fig. l is an isometric view of a push button switch embodying the present invention, with a portion of the housing broken away;

Fig. 2 is a view in side elevation partly in a cross section of the device of Fig. l, the parts being shown in the positions assumed when the contacts are in normal open position; and

Fig. 3 is a view similar to the view of Fig. 2 with the parts being shown in the positions assumed when the contacts are in closed position.

Referring to the drawing, the switch comprises a hous ing which has a main body section 14, and two cover plates 12 and 16 which serve as closure plates for the housing. Suitable bolts (not shown) may be inserted in holes 18 and 20 to assemble the housing. Housing 10 may be constructed of suitable insulating material such as molded plastic and forms a hollow chamber for the reception of the switch mechanism. The housing 10 is provided with openings in one wall through which are adapted to be inserted four male taper pins 22, 24, 26 and 28, which may be connected to circuits, as desired. The male taper pins, in turn, are adapted to be plugged into four female taper pins of which three, labelled 30, 32 and 34, respectively, are shown. Each female pin is located at a corner of the housing. The female pins are suitably secured in the housing by fitting them into molded apertures of which complementary portions are provided by the main body section 14 and the cover plates 12 and 16. Stationary contacts 36 and 38 are secured to, or form a part of, the tops of two of the female taper pins at one side of the housing.

The female taper pins are provided with conventional retaining grooves around the circumference thereof for maintaining them securely in the housing 10. Three such grooves, 40, 42 and 44 are shown in taper pins 30, 32 and 34 respectively. Grooves 40 and 42 serve an additional purpose which will become apparent hereinafter.

Slidably positioned within an opening in the inner section 14 of housing 10 is a push button 43, one end of which extends beyond the housing 10. The other, or confined, end offpush button 43 has a head 45 which fits within a counterbore 46 of the housing and limits the outward movement of the push button. The head 45 is contact with one leg 48 of a metal member 50,,

a which is generally U-shaped, and whose base portion 52 is reduced in width and designed to slide in a channel 54 centered between and spacedfrom taper pins 30 and 32. The terminus of the other leg 56 of member 50 is pivotally mounted in a recess 58 formed in a thickened l corner 60 of the inner section 14. The base portion 52 of member 50 has an anchor 62 extending therefrom apertured to receive one end of a spring 64.

Apair of similar contact arms 66 and 68 are nested within the confines and. on opposite sides of a yoke 70 which may be formed of. a suitable insulating plastic material'and is provided with flanges 72 and 74 which define therebetween a channel in which spring 64 extends. A pin 76 is suitably secured to and extends between flanges 72 and 74. The ends of contact arms 66 and 68 are pivoted in the grooves 40 and 42, respectively, which results in a slight wiping action when the arms are depressed. The other ends of the arms are provided with contacts 78 and 80 which are of customary construction and are adapted to be engaged with contacts 36 and 38, respectively.

Tension spring 64 secured between pin 76 and anchor 62 urges yoke and leg 52 of the member 50 toward each other and tends to move said yoke and U-shaped member about their pivots thus forming the active actuating means for the switch mechanism shown. Since the initial position of anchor 62 is above the pivotal points of the yoke 70 defined by the grooves 40 and 42, spring 64 will force the yoke 70 and the U-shaped member 50 upward, and the contacts 78 and will be lifted out of engagement with the fixed contacts 36 and 38, respectively.

The initial position of the anchor 62 above the pivotal points 40 and 42 will tend to maintain the circuit open until push button 43 is pressed into the housing against arm 48 (Fig. 3), pivoting U-shaped member 50 downward about its pivot in recess 58. This movement of the U-shaped member 50 will move anchor 62 and the longitudinal axis of spring 64 over its dead-center position to a position below the center pivotal points 40 and 42. Since this action is cumulative, the tensioned spring 64 acting between anchor 62 and the pin 76 will suddenly force the yoke 70 downward and the contact arms 66 and 68 will snap downward to establish engagement between contacts 78, 80 and fixed contacts 36, 38 respectively. At the same time arm 56 of the transfer device 50 snaps to a position against its stop wall 82 as shown in Fig. 3. Preferably, cont-act arms 66 and 68 are flexible so that they yield somewhat, allowing the contacts 78 and 80 to move a short distance across contacts 36 and 38, respectively, providing for a wiping action therebetween.

In the arrangement shown, in order to keep the switch closed and the contacts in engagement (Fig. 3), the push button must be held depressed in the housing 10. When push button 43 is released from its pressure against leg 48 of the U-shaped member 50, the tensioned spring 64 acting betweeen anchor 62 and pin 76 immediately retracts member 50 and yoke 70 upward (Fig. 2). The anchor 62 now being above pivot points 40 and 42, spring 64 pulls yoke 70 upward to its normal position and the associated contact arms are separated from the fixed contacts with a snap action, until it is stopped by contact of the leg 48 with the push button 43. A curved tip 84 provided on the free end of leg 48 provides a ready sliding engagement with the yoke 70,

that" is requisite in order' to close' the circuit is' a light pressure on push button 43; In fact, the snap action of the L l-shaped member and the contact arms. can be feltby'theoperator. A variationioi't the finger pressure on the push button will not have any elfect on the. engage:- ment or' disengagement of the switclicontacts;

-While there has been described what is' at'present' considered a preferred embodiment of the invention, it will, be obvious to, those skilled in theart that various changes and modifications may be made therein without departing from the invention; and it is therefore aimed in the appended claim to cover all such changes and modifications as fall withinv the true spirit and scope of the invention,

What is claimed, is: 7

An electric switch; comprising a housing, a fixed contact therein, a movable contact arm carrying a switch contact element at one. end for engagement with said fixed contact, a taper pin in saidhousing; meanspivot'ally mounting said movable contact at the other end'incl'udinga groove. in said) taper pin,ua substantially U-shaped member with one of its legs projecting over said movable contact arm and the other of its' legs pivotally mounted in said housing for actuating said movable contact arm, an anchor on the base portion of said U-shaped member, a spring secured between said anchor and said movable contact arm for normally biasing said anchor on one side of dead-center position of said spring to urge said contact arm away from said fixedcontact, wherein a pressure on said U-shaped member will move said anchor to the other side of'dead-center position; of saidspring with a snap action; thereby urging said contact arm into engagement with said fixed contact, and means for applying said pressure on said U-slia'pedi member. 

